Adsorption performance and mechanism of As(V) uptake over mesoporous Y–Al binary oxide

• Mesoporous Y–Al binary oxide was successfully synthesized.
• The adsorption performances were investigated by batch and column experiments.
• As(V) removal performance of mesoporous Y–Al binary oxide was heavily improved.
• Uptake mechanisms were illustrated by FT-IR and pH change.

Mesoporous Y–Al binary oxide was synthesized and employed as adsorbent to remove As(V) from aqueous solution in this study. The adsorbent was synthesized via incipient-wetness impregnation method, and then characterized by N2 adsorption–desorption, XRD, TEM, EDS and FT-IR. The adsorption performance was tested by batch and column experiments. From the results of batch experiments, it was found that the adsorption processes were abided by pseudo-second-order, which illustrated that the rate limiting step was the “surface reaction”. And Langmuir isotherm model was fitted well to the equilibrium experiment data at near neutral, and the maximum adsorption capacity was 62.23 mg/g. Additionally, the coexisting anions of nitrate, silicate and sulphate have no significant interfering effect on As(V) uptake, while the presence of fluoride and phosphate caused the markedly reduction. According to the results of FT-IR spectrum and the pH change in the adsorption process, it could be concluded that the interaction between arsenate and hydroxyl group was involved in the adsorption process. From the results of column experiments, it can be observed that the breakthrough time was increased from 83 min to 125 min due to the incorporation of Y(III) oxide.

During pHpHpzc (8.86), after OH− adsorbed over adsorbent Y–Al oxide at the first 5 min, the ion exchange between As(V) species and the adsorbed OH− was occurred.Figure optionsDownload as PowerPoint slide